Separation of Periodate, Iodate and Iodide on a C-18 Stationary Phase. Dependence of the Retention on the Temperature and Solvent Composition. Monitoring of an Oxidative Cleavage Reaction

Abstract

The separation of periodate, iodate and iodide can be easily achieved by HPLC on a C-18 column with a mobile phase consisting of acetonitrile and aqueous phosphoric acid, without the need of any mobile phase additives that are often employed. All three iodine species are well separated. Separation factors as high as 16 are observed, and retention factors k between ∼0.5 and 8. The retention time of all three ions increases with increasing acetonitrile concentration. The retention time of periodate and iodide decreases with increasing temperature, however, it increases slightly for iodate. An application of the HPLC method that was developed is the monitoring of an oxidative cleavage reaction, the cleavage of the enone-group of the steroid 4-androstene-3,17-dione. Periodate is used as oxidative reagent for this reaction. During the reaction periodate is reduced to iodate, and eventually both iodine species will be present in the reaction mixture, besides the starting material and product. In the final product the remaining iodate ions will be reduced to iodide which can be quantified accurately using the developed HPLC method.